A soulmate (or soul mate) is a person with whom one has a feeling of deep or natural affinity. This may involve similarity, love, intimacy,sexuality, sexual activity, spirituality, or compatibility and trust.
Certainly, that covers a broad range. I have met lots of people I have a natural affinity to, male and female both. Call it chemistry or whatever - it is an instant connection. But I think a soulmate goes beyond that instant connection to something much deeper.
In my life, I can only think of one person who truly was a soulmate to me, and that would be my sister Heidi. I always think of a soulmate as someone who I completely understand and who completely understands me. Someone who knows why I do what I do even though it may not make sense to anyone else. Heidi, though she has been dead over 25 years now, was that person to me.
To most people, I think it delves along the more romantic line, thanks in part to Hollywood. They believe the soulmate is the one they should marry.
And, if we were following the Wikipedia definition, that sounds pretty darn good to me too! If you are fortunate to find such a person, I would suggest you hold on and marry him/her!
I don't know if I really believe in soulmates. Like I said, I'm on the fence about it. Perhaps I'm not romantic enough. But I do believe in the importance of people and relationships and that we do all we can to enrich them. You can take that "feeling of deep or natural affinity" and make it grow even stronger. And when that starts to fade because of hurts or misunderstandings, we work at it, feed it and keep it alive, whether this is a marriage or just a good friend. It's a lot of work, to be sure, and sometimes painful, but it's worth it.